Elevators are used for lifting a load in a building. An elevator usually comprises an elevator car with which a load is transferred, as well as a counterweight. Elevator car and counterweight are adapted to move in opposite directions along vertical path in an elevator shaft.
The driving force for moving elevator car and counterweight is usually produced with a hoisting machine comprising an electric motor with a traction sheave coupled to the rotor of the electric motor. A hoisting roping runs via the traction sheave. The hoisting roping transmits the driving force produced by the electric motor to the elevator car and to the counterweight such that elevator car is moved in a controlled manner.
Conveyors, such as escalators and moving walkways, are used for transferring people by means of steps/pallets arranged to an endless track. A driving machine including an electric motor is usually arranged to drive the endless track by means of a sprocket or corresponding.
Supply of the electric power to the electric motor most generally occurs e.g. with a drive unit such as a frequency converter comprising power components as igbt transistors, mosfet transistors, bipolar transistors or other suitable controllable solid state switches.
In modern elevator systems without machine room, the hoisting machine and the drive unit are disposed in the elevator shaft such that a separate machine room is not needed. This type of solution saves building space. Space-saving is anyway a growing trend both in fabricating new elevators and in modernizing old elevators, in which case a new elevator system must be fitted into the existing old elevator shaft. Fitting a new elevator system into the existing old elevator shaft can be challenging owing to, inter alia, the small spaces available in the elevator shaft.
Space-saving is also a trend in conveyor systems, in which case aim is to utilize building space as efficiently as possible.
Taking the preceding into account, there is a need for improvement as regards to space-savings and space-efficiency.